I have had Citation X owners whine when I showed up in the Gulfstream: "Now I'll be late for my meeting." Believe me, there are people out there willing to pay for speed.
Richard Tracy from Aerion is a pretty smart guy. Brian Barents is on board too. If they can line up the risk sharing partners they need, I think they can get the product to market. Their plan does not require a regulatory change, uses off the shelf engines (by the way, the -219 Pratt is a later model of the JT8D engine and the quietest of the series), does not require exotic materials, and features a cabin that rivals the Falcon 50. Extensive Computational Fluid Dynamics computer modeling has verified the concept.
The real stumbling blocks I see are the barriers to entry of a small company playing with the big boy defense contractors who will try and keep Aerion from playing in their pond, and the hard-core, wackjob environmentalism sweeping the planet.